package org.dawnmew.simplejar;

/**
 * Allows JAR archives to be read and decompressed on-the-fly.
 *
 * @author dawnmew
 * @since 1.0
 *
 * Licensed under the MIT License.
 *
 * Copyright (c) 2012 dawnmew
 *
 * Permission is hereby granted, free of charge, to any person obtaining a copy
 * of this software and associated documentation files (the "Software"), to deal
 * in the Software without restriction, including without limitation the rights
 * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
 * copies of the Software, and to permit persons to whom the Software is
 * furnished to do so, subject to the following conditions:
 *
 * The above copyright notice and this permission notice shall be included in
 * all copies or substantial portions of the Software.
 *
 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
 * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
 * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
 * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
 * SOFTWARE.
 */
import java.io.IOException;
import java.io.InputStream;
import java.util.jar.JarFile;
import java.util.zip.ZipEntry;

public class JarReader
{

    private JarFile jarFile = null;

    public void openArchive(String filename)
    {
        if (isValid())
        {
            close();
        }
        try
        {
            jarFile = new JarFile(filename);
        } catch (IOException ex)
        {
            System.err.println("Couldn't read jar: " + filename);
        }
    }

    public boolean isValid()
    {
        return jarFile != null;
    }

    public InputStream getInputStream(String filename, boolean suppressFileNotFoundErrors)
    {
        if (!isValid())
        {
            return null;
        }
        ZipEntry entry = jarFile.getEntry(filename);
        if (entry == null)
        {
            if (!suppressFileNotFoundErrors)
            {
                System.err.println("Couldn't find file in jar: " + filename);
            }
            return null;
        }
        try
        {
            return jarFile.getInputStream(entry);
        } catch (IOException ex)
        {
            System.err.println("Couldn't open jar input stream: " + filename);
            return null;
        }
    }

    public InputStream getInputStream(String filename)
    {
        return getInputStream(filename, false);
    }

    public void close()
    {
        if (!isValid())
        {
            return;
        }
        try
        {
            jarFile.close();
        } catch (IOException ex)
        {
            System.err.println("Couldn't close JarReader instance.");
        }
        jarFile = null;
    }
}
